1. Technical Field
The present disclosure relates to a testing system, and more particularly to a testing system for testing conversion efficiency of a power supply.
2. Description of Related Art
Since the energy policy of different countries varies, most of the present power supply devices adopt a specification that maintains a conversion efficiency of the Power Supply Unit (PSU) over 80%. The conversion efficiency is the ratio of direct current (DC) output power to alternating current (AC) input power, expressed in percentage, with 100% being perfect. If a PSU requires an input of 400 W in AC to deliver 300 W in DC, then it has an efficiency of 75%, at this point, and 25% of the power is lost as heat within the power supply.
Referring to FIG. 4, a typical testing system for testing a conversion efficiency of a PSU 300 includes a AC source 100 applied to the PSU 300, a power meter 200, a first multimeter 400, a second multimeter 500, a first rotary switch 51, a second rotary switch S2, a third rotary switch S3, and a DC electronic load 600. The switches S1, S2, S3 are 1 pole 6 way switches. The power meter 200 is connected between the AC source 100 and the PSU 300 for measuring AC input power to the PSU 300. The PSU 300 output power rails include: 12V, 12 VCPU (a power rail for CPU), 5V, 3.3V, −12V, and 5 Vaux (standby voltage of 5V). Each of the power rails' output from the PSU 300 is supplied to the DC electronic load 600 via a resistor. The first rotary switch S1 is turned from one conducting position to another. Thus, the first multimeter 400 is capable of connecting to each of the power rails and measuring an effective output voltage of each of the power rails. The rotary switches S2, S3 are turned from one conduction position to another for connecting the second multimeter 500 to each of the resistors in a parallel connection. Thus, an output current of each of the power rails can be calculated using the formula: I=U/R. An output power of each of the power rails can be calculated by the formula: P=UI. A total output power of the PSU 300 equals the sum of all the output power of the power rails. Then the conversion efficiency of the PSU 300 equal to a ratio of the total output power of the PSU 300 to the AC input power can be calculated to determine whether the PSU 300 achieves the standard.
However, the typical testing system needs an operator to manually turn the rotary switches and record the current and voltage of each of the power rails, which is inefficient.